The goal of this research is to understand the mechanismms by which a freely grafted mammalian muscle survives the initial period of postoperative ischemia and how it becomes functionally reintegrated with the vascular and nervous systems of the host. Extensor digitorum longus or sternohyoid muscles in the rat are used as grafts. Muscular neurotization of sternohyoid grafts is under investigation - at this phase, the main question is to identify the signal that stimulates the sprouting of nerves in underlying normal muscles and their entry into the graft. In extensor digitorum longus grafts we are attempting to identify factors that result in the formation of functional neuromuscular contacts. Research on the viability of cells in the ischemic centers of early muscle grafts and the relationship to revascularization is continuing.